1. LING 408/508: Computational Techniques for Linguists
Lecture 24

2. Administrivia
Reminder: project proposals!

3. Today's Topic
Chapter 5 from the pythonbook: Objects and Graphics

4. graphics.py installation

5. Graphics Graphics is not usually part of a programming language
However, html5 has canvas and svg built-in
Traditionally:
Graphics  Libraries and Toolkits
Example:
Tk (designed by John Ousterhout as an extension to Tcl)
Tcl (Tool Command Language, also designed by John Ousterhout)
Tk was originally built on top of the (portable) X11 client-server window system for Unix but has also been ported to native, e.g. OSX, platform graphics

6. Graphics Zelle uses Tk: Tkinter: import graphics.py
Tkinter is Python's de-facto standard GUI (Graphical User Interface) package. It is a thin object-oriented layer on top of Tcl/Tk.

7. Tk
Examples:

8. Tcl
A simple programming language:

9. Tcl/Tk on Mac OS X

10. Tcl/Tk on Ubuntu

11. Tcl/Tk on Ubuntu

12. Tcl/Tk Examples Command line: wish interpreter for tcl/tk Concepts:
canvas place to draw
coordinate system (0,0) topleft
pack where to put canvas

13. graphics.py
Point: Implemented as a rectangle:

14. graphics.py
page 129

15. graphics.py
Call method draw() once only

16. graphics.py Rectangle: .draw() Oval: .draw() Circle: .getRadius()
Object inheritance (see graphics.py code):
_Bbox: move
Rectangle: .draw()
Oval: .draw()
Circle: .getRadius()
Line: .draw(), .setArrow()

17. Directly in tcl/tk Stylistic variation… tk: uses plain x,y coordinates
graphics.py: use primitive object Point
tk: uses plain x,y coordinates